This invention relates to a class of azabicyclic compounds which are useful as tachykinin antagonists. More particularly, the compounds of the invention are substituted benzylether derivatives of 1-phenyl-8-azabicyclo[3.2.1]octane, which are useful as neurokinin 1 (NK-1) receptor antagonists.
The present invention provides compounds of the formula (I): 
wherein
X represents hydrogen, C1-4alkyl optionally substituted by a hydroxy, methoxy or benzyloxy group, or CO2(C1-2alkyl);
Z is xe2x80x94CR9R10CH2xe2x80x94 or xe2x80x94CH2CR9R10xe2x80x94;
R1 is hydrogen, halogen, C1-6alkyl, C1-6alkoxy, fluoroC1-6alkyl, fluoroC1-6alkoxy, C3-7cycloalkyl, C3-7cycloalkylC1-4alkyl, NO2, CN, SRa, SORa, SO2Ra, CO2Ra, CONRaRb, C2-6alkenyl, C2-6alkynyl or C1-4alkyl substituted by C1-4alkoxy, wherein Ra and Rb each independently represent hydrogen or C1-4alkyl;
R2 is hydrogen, halogen, C1-6alkyl, fluoroC1-6alkyl or C1-6alkoxy substituted by C1-4alkoxy;
R3 is hydrogen, halogen or fluoroC1-6alkyl;
R4 represents hydrogen, halogen, C1-6alkyl, C1-6alkoxy, CF3, OCF3, NO2, CN, SRa, SORa, SO2Ra, CO2Ra, CONRaRb, C2-6alkenyl, C2-6alkynyl or C1-4alkyl substituted by C1-4alkoxy, where Ra and Rb are as previously defined;
R5 represents hydrogen, halogen, C1-6alkyl, CF3 or C1-6alkoxy substituted by C1-4alkoxy;
R6 represents hydrogen, hydroxy, CORa, CO2Ra, COCONRaRb, COCO2Ra, C1-6alkyl, C2-6alkenyl, or C1-6alkyl substituted by a group selected from CO2Ra, CONRaRb, hydroxy, CN, CORa, NRaRb, C(NOH)NRaRb, CONHphenyl(C1-4alkyl), COCO2Ra, CONHNRaRb, C(S)NRaRb, CONRaC1-6alkylR14, CONR11C2-6alkenyl, CONR11C2-6alkynyl, COCONRaRb, CONRaC(NRb)NRaRb, CONRaheteroaryl, and phenyl optionally substituted by one, two or three substituents selected from C1-6alkyl, C1-6alkoxy, halogen and trifluoromethyl;
or R6 represents a group of the formula xe2x80x94CH2Cxe2x89xa1CCH2NR7R8 where R7 and R8 are as defined below;
or R6 represents C1-6alkyl, optionally substituted by oxo, substituted by a 5-membered or 6-membered heterocyclic ring containing 1, 2 or 3 nitrogen atoms optionally substituted by xe2x95x90O or xe2x95x90S and optionally substituted by a group of the formula xe2x80x94Yxe2x80x94NR7R8 where
Y is C1-6alkylene or C3-6cycloalkyl;
R7 represents hydrogen or C1-4alkyl, C3-7cycloalkyl, C3-7cycloalkylC1-4alkyl, or C2-4alkyl substituted by C1-4alkoxy or hydroxyl;
R8 represents hydrogen or C1-6alkyl, C1-6alkoxy, C3-7cycloalkyl, C3-7cycloalkylC1-4alkyl, phenyl or C1-4alkyl substituted by a group selected from C1-4alkoxy, hydroxyl, CO2Ra, NRaRb, aryl, aryloxy, heteroaryl or a 4, 5 or 6 membered heteroaliphatic ring containing one or two heteroatoms selected from N, O and S;
or R7, R8 and the nitrogen atom to which they are attached form a heteroaliphatic ring of 4 to 7 ring atoms, optionally substituted by one or two groups selected from methyl, hydroxy, CO2(C1-2alkyl), phenyl, benzyl or C1-4alkoxy optionally substituted by a C1-4alkoxy or hydroxyl group, and optionally containing a double bond, which ring may optionally contain an oxygen or sulphur ring atom, a group S(O) or S(O)2 or a second nitrogen atom which will be part of a NH or NRc moiety where Rc is C1-4alkyl, hydroxyC1-4alkyl, C1-4alkoxyC1-4alkyl, phenyl or benzyl;
or R7, R8 and the nitrogen atom to which they are attached form a non-aromatic azabicyclic ring system of 6 to 12 ring atoms;
or Y, R7 and the nitrogen atom to which they are attached form a heteroaliphatic ring to 4 to 7 ring atoms which may optionally contain an oxygen ring atom;
R9 represents hydrogen, hydroxy, oxo, C1-6alkyl, C2-6alkenyl, C2-6alkynyl, C3-7cycloalkyl, C3-7cycloalkylC1-4alkyl, fluoroC1-6alkyl, C1-6alkoxy, fluoroC1-6alkoxy, hydroxyC1-6alkyl, C1-6alkoxyC1-4alkyl, C1-6alkoxyC1-4alkoxy, fluoroC1-6alkoxyC1-4alkyl, C2-6alkenyloxy, C2-6alkynyloxy, C3-7cycloalkoxy, C3-7cycloalkylC1-4alkoxy, aryl, aryl(CH2), aryloxy, aryl(CH2)oxy, cyano, halogen, NR7R8, CH2NR7R8, SR12, SOR12, SO2R12, OSO2R12, NRaCOR12, CH(OH)R12, COR12, CO2R12, CONR7R8, CONHNH2, CH2OR13, heteroaryl or heteroarylC1-4alkyl, wherein Ra is as previously defined;
R10 represents hydrogen, halogen or hydroxy;
R11 represents hydrogen or C1-6alkyl;
R12 represents hydrogen, C1-6alkyl, C1-6alkoxy, fluoroC1-6alkyl or phenyl optionally substituted by one, two or three substituents selected from C1-6alkyl, C1-6alkoxy, halogen or trifluoromethyl;
R13 represents C1-4alkyl substituted by a group selected from hydroxy, CORa, CO2Ra, CONRaRb and heteroaryl, where Ra is as previously defined;
R14 represents ORa, CONRaRb or heteroaryl;
and pharmaceutically acceptable salts or N-oxides thereof.
A preferred class of compound of formula (I) is that wherein X is hydrogen, methyl or hydroxymethyl.
Another preferred class of compound of formula (I) is that wherein R1 is hydrogen, C1-4alkyl, C1-4alkoxy, halogen or CF3.
Another preferred class of compounds of formula (I) is that wherein R2 is hydrogen, C1-4alkyl, C1-4alkoxy, halogen or CF3.
Also preferred is the class of compounds of formula (I) wherein R3 is hydrogen, fluorine, chlorine or CF3.
A particularly preferred class of compounds of formula (I) is that wherein R1 is fluorine, chlorine or CF3.
Another particularly preferred class of compounds of formula (I) is that wherein R2 is hydrogen, fluorine, chlorine or CF3.
Also particularly preferred is the class of compounds of formula (I) wherein R3 is hydrogen, fluorine, chlorine or CF3.
Preferably R1 and R2 are in the 3 and 5 positions of the phenyl ring.
More preferably R1 is 3-fluoro or 3-CF3.
More preferably R2 is 5-fluoro or 5-CF3.
More preferably R3 is hydrogen.
Most preferably R1 is 3-F or 3-CF3, R2 is 5-CF3 and R3 is hydrogen.
A further preferred class of compound of formula (I) is that wherein R4 is a hydrogen atom or a fluorine atom.
Another preferred class of compound of formula (I) is that in which R5 is a hydrogen atom.
A further preferred class of compound of formula (I) is that wherein R6 is a hydrogen atom or a C1-6alkyl group (especially methyl) or a C1-3alkyl group, in particular CH2, CH(CH3) and CH2CH2 and especially CH2, substituted by a 5-membered heterocyclic ring containing 2 or 3 nitrogen atoms as previously defined.
In particular, the 5-membered ring is a heterocyclic ring selected from 1,3-imidazol-4-yl, 1,2,4-triazol-3-yl, 1,2,3-triazol-4-yl, 2-oxo-1,3-imidazol-4-yl and 3-oxo-1,2,4-triazol-5-yl, any of which rings being optionally substituted by the group xe2x80x94Yxe2x80x94NR7R8.
Particularly preferred heterocyclic rings are selected from: 
Most especially, the 5-membered heterocyclic ring is a 1,2,4-triazol-3-yl or 3-oxo-1,2,4-triazol-5-yl group.
Another preferred class of compound of formula (I) is that wherein R9 represents hydrogen, hydroxy, oxo, C1-6alkoxy, C1-6alkoxyC1-4alkyl, hydroxyC1-4alkyl, cyano, NR7R8, CH2NR7R8, SO2Rd, CH(OH)R12, COR12, CO2R12, CONR7R8, phenyl, heteroaryl, heteroarylC1-4alkyl or CH2OR13, where said phenyl is optionally substituted by one or two substituents selected from C1-4alkyl, C1-4alkoxy, halogen or trifluoromethyl.
A further preferred class of compound of formula (I) is that wherein R9 represents hydrogen, hydroxy, C1-4alkoxyC1-2alkyl (especially methoxymethyl), hydroxyC1-2alkyl (especially hydroxymethyl), cyano, CH2NR7R8, SO2R12 (especially where R12 is phenyl), CH(OH)R12 (especially where R12 is phenyl), COR12 (especially where R12 is phenyl), CO2R12 (especially where R12 is C1-2alkyl, e.g. methyl), CONR7R8, heteroaryl, or CH2OR13.
When the group R9 represents NR7R8, CH2NR7R8 or CONR7R8, R7 is preferably hydrogen, or C1-4alkyl (especially methyl); and R8 is preferably hydrogen, C1-6alkyl, C1-4alkoxy or C1-3alkyl substituted by a group selected from methoxy, hydroxy, amino, methylamino, dimethylamino, phenyl, phenyloxy, or heteroaryl, wherein said phenyl or phenyloxy groups may be optionally substituted by one, two or three halogen atoms or methoxy groups, and wherein said heteroaryl group is preferably furanyl, thienyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, triazolyl, pyridyl or quinolinyl, each of which heteroaryl groups may be optionally substituted by a methyl or phenyl group; or R7 and R8, together with the nitrogen atom to which they are attached, represent a heteroaliphatic ring selected from azetidinyl, pyrolidinyl, piperidinyl, morpholinyl, or piperazinyl, wherein said piperidinyl group may be optionally substituted by a methyl, CO2(C1-2alkyl), phenyl or benzyl group and, optionally, a hydroxy group, and wherein said piperazinyl group may be optionally substituted on the free nitrogen atom by a phenyl or benzyl group.
When the group R9 represents a heteroaryl group, said group is preferably oxazolyl, thiazolyl, triazolyl or tetrazolyl, each of which groups may be optionally substituted by C1-4alkyl, C1-2alkoxyC1-2alkyl, hydroxyC1-4alkyl, fluoroC1-4alkyl, CH2CONRaRb, CH2CORa, CH2CO2Ra, CH2SR12, CH2SOR12 or CH2SO2R12.
Another preferred class of compounds of formula (I) is that wherein R10 represents hydrogen, fluorine or hydroxy, and in particular that wherein R10 is hydrogen.
One favoured group of compounds of the present invention are of the formula (Ia) and pharmaceutically acceptable salts thereof: 
wherein R1, R3, R4 and X are as defined in relation to formula (I) and Z is preferably xe2x80x94CR9R10OCH2xe2x80x94.
With respect to compounds of the formula (I), Y (where present), may be a linear, branched or cyclic group. Favourably Y contains 1 to 4 carbon atoms and most favourably 1 or 2 carbon atoms. A particularly favourable group Y is CH2.
Where the group NR7R8 represents a heteroaliphatic ring of 4 to 7 ring atoms and said ring contains a double bond, a particularly preferred group is 3-pyrroline.
Where the group NR7R8 represents a non-aromatic azabicyclic ring system, such a system may contain between 6 and 12, and preferably between 7 and 10, ring atoms. Suitable rings include
5-azabicyclo[2.1.1]hexyl, 5-azabicyclo[2.2.1]heptyl, 6-azabicyclo[3.2.1]octyl,
2-azabicyclo[2.2.2]octyl, 6-azabicyclo[3.2.2]nonyl, 6-azabicyclo[3.3.1]nonyl,
6-azabicyclo[3.2.2]decyl, 7-azabicyclo[4.3.1]decyl,
7-azabicyclo[4.4.1]undecyl and 8-azabicyclo[5.4.1]dodecyl, especially
5-azabicyclo[2.2.1]heptyl and 6-azabicyclo[3.2.1]octyl.
Where R8 represents a C1-4alkyl group substituted by a 4, 5 or 6 membered heteroaliphatic ring containing one or two heteroatoms selected from N, O and S, suitable rings include azetidinyl, pyrrolidino, piperidino, piperazino, morpholino, or thiomorpholino. Particularly preferred are nitrogen containing heteroaliphatic rings, especially pyrrolidino and morpholino rings.
Particularly suitable moieties xe2x80x94Yxe2x80x94NR7R8 include those wherein Y is CH2 or CH2CH2 and xe2x80x94NR7R8 is amino, methylamino, dimethylamino, diethylamino, azetidinyl, pyrrolidino and morpholino.
In particular, Y is preferably CH2 and NR7R8 is preferably dimethylamino, azetidinyl or pyrrolidino, especially dimethylamino.
When any variable occurs more than one time in formula (I) or in any substituent, its definition on each occurrence is independent of its definition at every other occurrence.
It will be appreciated that, where R9 represents an oxo (xe2x95x90O) group, then R10 will be absent and the group Z will in fact represent xe2x80x94C(O)CH2xe2x80x94 or xe2x80x94CH2C(O)xe2x80x94.
As used herein, the term xe2x80x9calkylxe2x80x9d or xe2x80x9calkoxyxe2x80x9d as a group or part of a group means that the group is straight or branched. Examples of suitable alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl and t-butyl. Examples of suitable alkoxy groups include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, s-butoxy and t-butoxy.
As used herein, the terms xe2x80x9cfluoroC1-6alkylxe2x80x9d and fluoroC1-6alkoxyxe2x80x9d mean a C1-6alkyl or C1-6alkoxy group in which one or more (in particular, 1 to 3) hydrogen atoms have been replaced by fluorine atoms. Similarly, the term xe2x80x9cfluoroC1-4alkylxe2x80x9d means a C1-4alkyl group in which one or more (in particular 1 to 3) hydrogen atoms have been replaced by fluorine atoms. Particularly preferred are fluoroC13alkyl and fluoroC13alkoxy groups, for example, CF3, CH2CH2F, CH2CHF2, CH2CF3, OCF3, OCH2CH2F, OCH2CHF2 or OCH2CF3, and most especially CF3, OCF3 and OCH2CF3.
As used herein, the term xe2x80x9chydroxyC1-6alkylxe2x80x9d means a C1-6alkyl group, in which one or more (in particular 1 to 3) hydrogen atoms have been replaced by a hydroxy group. Preferred are hydroxyC1-3alkyl groups, especially where one hydrogen atom has been replaced by a hydroxy group, for example, CH2OH, CH2CH2OH and C(CH3)2OH.
The cycloalkyl groups referred to herein may represent, for example, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl. A suitable cycloalkylalkyl group may be, for example, cyclopropylmethyl.
Similarly cycloalkoxy groups referred to herein may represent, for example, cyclopropoxy or cyclobutoxy.
As used herein, the terms xe2x80x9calkenylxe2x80x9d and xe2x80x9calkynylxe2x80x9d as a group or part of a group means that the group is straight or branched. Examples of suitable alkenyl groups include vinyl and allyl. A suitable alkynyl group is propargyl.
As used herein, the term xe2x80x9carylxe2x80x9d as a group or part of a group means a monocyclic, fused-bicyclic or linear bicyclic aromatic ring containing 6, 10 or 12 carbon atoms, any of which rings is optionally substituted by one, two or three substituents selected from halogen, C1-6alkyl, C1-6alkoxy, or trifluoromethyl. Particular examples of such groups include phenyl, naphthyl and biphenyl. Phenyl is especially preferred.
As used herein, the term xe2x80x9cheteroarylxe2x80x9d as a group or part of a group means a monocyclic or fused-bicylic heteroaromatic ring containing between 5 and 10 ring members, of which 1 to 4 may be heteroatoms selected from N, O and S, and wherein any of which rings is optionally substituted by one or two substituents selected from halogen, C1-6alkyl, C1-6alkoxy, CO2Ra, trifluoromethyl or phenyl. Particular examples of such groups include pyrrolyl, furanyl, thienyl, pyridyl, pyrazolyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazolyl, oxadiazolyl, thiadiazolyl, triazinyl, tetrazolyl, indole, benzofuran, benzthiophene, benzimidazole, benzoxazole, benzthiazole and quinolinyl. Furanyl, thienyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, triazolyl, tetrazolyl and pyridyl are particularly preferred. Where said rings are substituted, preferred substituents include methyl and phenyl groups.
When used herein the term xe2x80x9chalogenxe2x80x9d means fluorine, chlorine, bromine and iodine. The most apt halogens are fluorine and chlorine of which fluorine is preferred, unless otherwise stated.
In a further aspect of the present invention, the compounds of formula (I) may be prepared in the form of a pharmaceutically acceptable salt, especially an acid addition salt.
For use in medicine, the salts of the compounds of formula (I) will be non-toxic pharmaceutically acceptable salts. Other salts may, however, be useful in the preparation of the compounds according to the invention or of their non-toxic pharmaceutically acceptable salts. Suitable pharmaceutically acceptable salts of the compounds of this invention include acid addition salts which may, for example, be formed by mixing a solution of the compound according to the invention with a solution of a pharmaceutically acceptable acid such as hydrochloric acid, fumaric acid, p-toluenesulphonic acid, maleic acid, succinic acid, acetic acid, citric acid, tartaric acid, carbonic acid, phosphoric acid or sulphuric acid. Salts of amine groups may also comprise quaternary ammonium salts in which the amino nitrogen atom carries a suitable organic group such as an alkyl, alkenyl, alkynyl or aralkyl moiety. Furthermore, where the compounds of the invention carry an acidic moiety, suitable pharmaceutically acceptable salts thereof may include metal salts such as alkali metal salts, e.g. sodium or potassium salts; and alkaline earth metal salts, e.g. calcium or magnesium salts.
The salts may be formed by conventional means, such as by reacting the free base form of the product with one or more equivalents of the appropriate acid in a solvent or medium in which the salt is insoluble, or in a solvent such as water which is removed in vacuo or by freeze drying or by exchanging the anions of an existing salt for another anion on a suitable ion exchange resin.
The present invention includes within its scope prodrugs of the compounds of formula (I) above. In general, such prodrugs will be functional derivatives of the compounds of formula (I) which are readily convertible in vivo into the required compound of formula (I). Conventional procedures for the selection and preparation of suitable prodrug derivatives are described, for example, in xe2x80x9cDesign of Prodrugsxe2x80x9d, ed. H. Bundgaard, Elsevier, 1985.
A prodrug may be a pharmacologically inactive derivative of a biologically active substance (the xe2x80x9cparent drugxe2x80x9d or xe2x80x9cparent moleculexe2x80x9d) that requires transformation within the body in order to release the active drug, and that has improved delivery properties over the parent drug molecule. The transformation in vivo may be, for example, as the result of some metabolic process, such as chemical or enzymatic hydrolysis of a carboxylic, phosphoric or sulphate ester, or reduction or oxidation of a susceptible functionality.
The present invention includes within its scope solvates of the compounds of formula (I) and salts thereof, for example, hydrates.
The compounds according to the invention have at least three asymmetric centres, and may accordingly exist both as enantiomers and as diastereoisomers. It is to be understood that all such isomers and mixtures thereof are encompassed within the scope of the present invention.
The preferred compounds of formula (I) and (Ia) will have the stereochemistry of the 1, 2 and 5 positions as possessed by, for instance, the compound of Example 1, i.e. as shown in formula (Ib) 
It will be appreciated that the preferred definitions of the various substituents recited herein may be taken alone or in combination and, unless otherwise stated, apply to the generic formula for compounds of the present invention as well as to the preferred class of compound represented by formula (Ia) and formula (Ib).
The present invention further provides pharmaceutical compositions comprising one or more compounds of formula (I) in association with a pharmaceutically acceptable carrier or excipient.
Preferably the compositions according to the invention are in unit dosage forms such as tablets, pills, capsules, powders, granules, solutions or suspensions, or suppositories, for oral, parenteral or rectal administration, or administration by inhalation or insufflation. Oral compositions such as tablets, pills, capsules or wafers are particularly preferred.
A more detailed description of pharmaceutical compositions that are suitable for the formulation of compounds of the present invention is disclosed in U.S. Pat. No. 6,071,927, the content of which is incorporated herein by reference (see in particular, column 8, line 50 to column 10, line 4).
The present invention further provides a process for the preparation of a pharmaceutical composition comprising a compound of formula (I), which process comprises bringing a compound of formula (I) into association with a pharmaceutically acceptable carrier or excipient.
The compounds of formula (I) are of value in the treatment of a wide variety of clinical conditions which are characterised by the presence of an excess of tachykinin, in particular substance P, activity. A comprehensive listing of clinical conditions, uses and methods of treatment for which the compounds of the present invention will be useful is disclosed in U.S. Pat. No. 6,071,927, the content of which is incorporated herein by reference (see, in particular, column 10, line 14 to column 22, line 18).
In particular, the compounds of the present invention are useful in the treatment of a variety of disorders of the central nervous system. Such disorders include mood disorders, such as depression or more particularly depressive disorders, for example, single episodic or recurrent major depressive disorders and dysthymic disorders, or bipolar disorders, for example, bipolar I disorder, bipolar II disorder and cyclothymic disorder; and anxiety disorders, such as panic disorder with or without agoraphobia, agoraphobia without history of panic disorder, specific phobias, for example, specific animal phobias, social phobias, obsessive-compulsive disorder, stress disorders including post-traumatic stress disorder and acute stress disorder, and generalised anxiety disorders.
The compounds of the present invention are also particularly useful in the treatment of nociception and pain. Diseases and conditions in which pain predominates, include soft tissue and peripheral damage, such as acute trauma, osteoarthritis, rheumatoid arthritis, musculo-skeletal pain, particularly after trauma, spinal pain, myofascial pain syndromes, headache, migraine, episiotomy pain, and burns.
The compounds of the present invention are also particularly useful in the treatment of respiratory diseases, particularly those associated with excess mucus secretion, such as chronic obstructive airways disease, bronchopneumonia, chronic bronchitis, cystic fibrosis and asthma, adult respiratory distress syndrome, and bronchospasm; in the treatment of inflammatory diseases such as inflammatory bowel disease, psoriasis, fibrositis, osteoarthritis, rheumatoid arthritis, pruritis and sunburn; and in the treatment of allergic disorders such as eczema and rhinitis.
The compounds of the present invention are also particularly useful in the treatment of gastrointestinal (GI) disorders, including inflammatory disorders and diseases of the GI tract such as ulcerative colitis, Crohn""s disease and irritable bowel syndrome.
The compounds of the present invention are also particularly useful in the treatment of emesis, including acute, delayed or anticipatory emesis, such as emesis induced by chemotherapy, radiation, toxins, pregnancy, vestibular disorders, motion, surgery, migraine, and variations in intercranial pressure. Most especially, the compounds of formula (I) are of use in the treatment of emesis induced by antineoplastic (cytotoxic) agents, including those routinely used in cancer chemotherapy; by radiation including radiation therapy such as in the treatment of cancer; and in the treatment of post-operative nausea and vomiting.
The excellent pharmacological profile of the compounds of the present invention offers the opportunity for their use in therapy at low doses thereby minimising the risk of unwanted side effects.
In the treatment of the conditions associated with an excess of tachykinins, a suitable dosage level is about 0.001 to 50 mg/kg per day, in particular about 0.01 to about 25 mg/kg, such as from about 0.05 to about 10 mg/kg per day.
For example, in the treatment of conditions involving the neurotransmission of pain sensations, a suitable dosage level is about 0.001 to 25 mg/kg per day, preferably about 0.005 to 10 mg/kg per day, and especially about 0.005 to 5 mg/kg per day. The compounds may be administered on a regimen of 1 to 4 times per day, preferably once or twice per day.
In the treatment of emesis, a suitable dosage level is about 0.001 to 10 mg/kg per day, preferably about 0.005 to 5 mg/kg per day, and especially 0.01 to 3 mg/kg per day. The compounds may be administered on a regimen of 1 to 4 times per day, preferably once or twice per day.
In the treatment of psychiatric disorders, a suitable dosage level is about 0.001 to 10 mg/kg per day, preferably about 0.005 to 5 mg/kg per day, and especially 0.01 to 3 mg/kg per day. The compounds may be administered on a regimen of 1 to 4 times per day, preferably once or twice per day.
It will be appreciated that the amount of a compound of formula (I) required for use in any treatment will vary not only with the particular compounds or composition selected but also with the route of administration, the nature of the condition being treated, and the age and condition of the patient, and will ultimately be at the discretion of the attendant physician.
As used herein, the term xe2x80x9ctreatmentxe2x80x9d includes prophylactic use to prevent the occurrence or recurrence of any of the aforementioned conditions.
According to a general process (A), compounds of formula (I) may be prepared by the reaction of a compound of formula (II) with a compound of formula (III) 
wherein LG represents a leaving group; in the presence of a base, followed by deprotection, if required.
Suitable leaving groups include halo, for example, chloro, bromo or iodo, or sulphonate derivatives such as tosylate, mesylate or triflate.
Favoured bases of use in the reaction include alkali metal amides and hydrides, such as potassium bis(trimethylsilyl)amide, sodium hydride or potassium hydride.
The reaction is conveniently carried out in a suitable organic solvent, such as dimethylformamide or an ether, for example, 1,2-dimethoxyethane, at a temperature in the region of 0xc2x0 C.
According to another general process (B), compounds of formula (I), in which X is methyl or hydroxymethyl, may be prepared by the reaction of a compound of formula (IV) 
under either:
(a) (where R6 is methyl) catalytic hydrogenation conditions (e.g. H2, Pd(OH)2 on carbon) in a suitable solvent such as an ester, for example, ethyl acetate or an alcohol, for example, ethanol, or a mixture thereof; or (b) (where R6 is hydroxymethyl) reducing conditions (e.g. borane or BH3.THF) followed by treatment with hydrogen peroxide and a base such as sodium hydroxide, conveniently in a solvent such as an ether, for example, tetrahydrofuran, or water, or a mixture thereof.
According to another general process (C), compounds of formula (I) may be prepared by the interconversion of a corresponding compound of formula (I) in which R6 is H, hereinafter referred to as formula (V) 
by reaction with a compound of formula (VI):
LG-R6axe2x80x83xe2x80x83(VI)
where R6a is a group of the formula R6 as defined in relation to formula (I) (other than H) or a precursor therefor and LG is a leaving group such as an alkyl- or arylsulphonyloxy group (e.g. mesylate or tosylate) or a halogen atom (e.g. bromine, chlorine or iodine); and, if R6a is a precursor group, converting it to a group R6 (in which process any reactive group may be protected and thereafter deprotected if desired).
This reaction may be performed in conventional manner, for example in an organic solvent such as dimethylformamide in the presence of an acid acceptor such as potassium carbonate.
Suitable alternative methods for introducing the group R6 are described, for instance, in International Patent Specification No. WO 95/18124.
According to another general process (D), compounds of formula (I), wherein X is hydrogen, may be prepared by the reduction of a compound of formula (VII) 
Suitable reducing conditions include: catalytic hydrogenation using a metal catalyst such as palladium or platinum or hydroxides or oxides thereof, preferably in a suitable solvent such as alcohol, e.g. methanol or ethanol, or an ester, e.g. ethyl acetate, or an organic acid e.g. acetic acid, or a mixture thereof; or reduction using trifluoroacetic acid and triethylsilane.
According to another general process (E), compounds of formula (I), wherein X is CO2CH3 may be prepared by the reaction of a compound of formula (II) with a diazo compound of formula (VIII) 
The reaction is conveniently effected in the presence of a rhodium catalyst such as rhodium (II) acetate dimer, in a suitable solvent such as a halogenated hydrocarbon, for example, 1,2-dichloroethane, or an aromatic hydrocarbon, for example, benzene. The reaction is preferably effected at an elevated temperature, for example at the reflux temperature of the solvent.
Compounds of formula (I) wherein X is CH2OH or CH3 may be prepared from a corresponding compound of formula (I) wherein X is CO2CH3 by convention methodology. For instance, by reduction to the primary alcohol using a borohydride such as sodium borohydride in a suitable solvent such as an alcohol, for example, methanol, at a reduced temperature, for example, at between 0xc2x0 C. and 15xc2x0 C., preferably at between 5xc2x0 C. and 10xc2x0 C. The corresponding compound of formula (I) wherein X is CH3 may be prepared from the primary alcohol by a two-step reaction. Firstly, reaction with iodine in the presence of imidazole and triphenylphosphine converts the CH2OH group to a CH2I group. The desired compound is then obtained by treatment of the iodide under conditions of catalytic hydrogenation, for instance, hydrogen in the presence of palladium on charcoal catalyst and triethylamine, in a suitable solvent such as methanol.
Further details of suitable procedures will be found in the accompanying Examples.
Intermediates of formula (II) may be prepared by reduction of a corresponding compound of formula (IX): 
Suitable reducing agents will be readily apparent to one skilled in the art and include, for example, metallic hydrides, such as lithium aluminium hydride or, preferably, sodium borohydride. The reduction is conveniently effected in a suitable solvent such as an ether, for example, tetrahydrofuran, or an alcohol, for example, methanol, or a mixture thereof.
Where they are not commercially available, the intermediates of formula (III) above may be prepared by the procedures described in the accompanying Examples or by alternative procedures which will be readily apparent to one skilled in the art.
Compounds of formula (IX) may be prepared from a compound of formula (X) 
by catalytic hydrogenation using a metal catalyst such as palladium or platinum or hydroxides or oxides thereof, preferably in a suitable solvent such as alcohol, for example, methanol or ethanol, or an ester, for example, ethyl acetate, or an organic acid, for example, acetic acid, or a mixture thereof.
Intermediates of formula (II) may also be prepared from a compound of formula (X) by treatment with K-Selectride(trademark) (potassium tri-sec-butylborohydride) in tetrahydrofuran.
Compounds of formula (X), wherein R6 is xcex1-methylbenzyl, benzyl or allyl, may be prepared from a compound of formula (XI) 
(or a corresponding compound wherein the Oxe2x88x92 is OH, and the compound is associated with a counterion, such as a bromide or chloride ion) by reaction with a vinyl compound of the formula R9CHxe2x95x90CH2, in particular where R9 is cyano, SO2R13 (especially where R13 is phenyl) or CO2R13 (especially where R13 is tert-butyl), in the presence of an organic base such as a trialkylamine, for example, triethylamine. The reaction is conveniently effected in an aprotic solvent such as an aromatic hydrocarbon, for example, toluene.
The reaction of a compound of formula (XI) with acrylonitrile is particularly suitable for preparing compounds where the R9 substituent is situated on either of the carbon atoms of the two-carbon bridge.
Compounds of formula (IV) may be prepared from a compound of formula (XII) 
by reaction with dimethyltitanocene in a solvent such as toluene, pyridine or tetrahydrofuran, or a mixture thereof.
Compounds of formula (XII) may be prepared by the reaction of a compound of formula (II) with L-Selectride(trademark) (lithium tri-sec-butylborohydride) followed by treatment with a compound of formula (XIII) 
wherein Hal is a halogen atom, preferably chlorine.
Compounds of formula (VII) may be prepared by reaction of a compound of formula (XIV) 
with a compound of formula (III) according to the method of general process (A), above.
Compounds of formula (XIII) may be prepared from the corresponding compound of formula (X) by reduction using, for example, metallic hydrides, such as lithium aluminium hydride or, preferably, sodium borohydride. The reduction is conveniently effected in a suitable solvent such as an ether, for example, tetrahydrofuran, or an alcohol, for example, methanol, or a mixture thereof.
In a preferred embodiment of the aforementioned processes, R6 is a benzyl group. The various reduction reactions described above may conveniently replace the benzyl group with a hydrogen atom. It will be appreciated from the discussion above that compounds of formula (I) wherein R6 is a hydrogen atom are particularly preferred precursors to other compounds of formula (I).
Compounds of formula (VIII) are either known compounds or may be prepared by methods analogous to those known in the literature (see, for instance, R. T. Lewis et al., J. Org. Chem. (2000) 65:2615).
Compounds of formula (XI) and (XIII) are either known compounds or may be prepared by methods analogous to those described herein.
It will be appreciated that the general methodology described above may be adapted, using methods that are readily apparent to one of ordinary skill in the art, in order to prepare further compounds of the present invention.
During any of the above synthetic sequences it may be necessary and/or desirable to protect sensitive or reactive groups on any of the molecules concerned. This may be achieved by means of conventional protecting groups, such as those described in Protective Groups in Organic Chemistry, ed. J. F. W. McOmie, Plenum Press, 1973; and T. W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, John Wiley and Sons, 1991. The protecting groups may be removed at a convenient subsequent stage using methods known from the art.
The exemplified compounds of this invention were tested by the methods set out at pages 36 to 39 of International Patent Specification No. WO 93/01165. The compounds were found to be active with IC50 at the human NK1 receptor of less than 100 nM on said test method.